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2006 SAAB 93 Aero - Rough idle and Rough when accelerating out of 50-55mph

30K views 29 replies 14 participants last post by  Cosmicflash 
#1 ·
2006 SAAB 93 Aero - 53k miles

Recent Service:
Within the last 6 months I have replaced the battery, spark plugs, and had my shop ran some sea foam through the system at the time the spark plugs were replaced.

Symptoms:

Idle is rough when stopped, almost as if the engine is trying to quit. The engine runs fine under normal power most of the time. However, when cruising down the highway at about 50-55 mph, it sputters when you gently apply throttle. If you aggressively apply throttle there is little issue.

Now, prior to the most recent service, under full throttle to pass a slower car the engine put itself into limp mode. After a shutdown and restart, no codes were thrown at the shop a few hours later. I've shut the car down a few times to eliminate the rough engine after full throttle.

Questions:

I've read up on some other threads about the rough idle issue, but wanted to get some additional input based on my issue under throttle at cruise. Typically the RPM's are low at 50-55 and it almost feels like the tranny is slipping, but the shop has assured me that's not the issue. Any guidance on where to start chasing gremlins would be appreciated.

Thanks in advance!
 
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#2 ·
Hmmmm....

Limp mode and no CEL's--that just kills me how the Bosch ME9 is so unsensitive or uncommunicative.

I've had my 06' go into limp mode due to a bad Boost Control Valve however that was under full throttle and a cel would be thrown with an overboost code. Also when the tranny would act up.

Your symptoms sound like a miss and that could possible be a bad coil pack. Have those been checked?
Or it could just be the torque converter locking and unlocking. It may appear to lug but probably not.
It doesn't sound like a tranny issue however the valve bodies have had problems on this 6 speed. Only shifting concerns however would indicate a problematic valve body.
And don't count on the TCM in the tranny to do anything. It is less sensitive than the Bosch ME9:(
 
#19 ·
2004 saab 9-3 2.0t w/ same issue

I have a 2004 Saab 9-3 w/ a 2.0t that had the same issues as the ones listed below...or above? My car has about 97K on it. After having this issue this morning I read all of these suggestions and comments and decided just to replace all four of the ignition coil pack(s) and my car runs better than new. So thank you all for your help, it was a very easy/quick task.

I should also add, that I replaced all spark plugs as well.

thanks again
 
#4 ·
I believe they checked the coils at the last service. They also checked for a vacuum leak at the time found nothing.

now I did some trouble shooting during the past week. It doesn't seem to make a difference whether it's in neutral or drive when stopped. It does seem to be more pronounced when the AC is on. It was running rough at a light and I switched the AC off and it almost completely stopped running rough. The RPMs also dropped to between 700-800 but it was smoother than the idle at 900ish.

Any thoughts on how the extra load on the engine from the AC might create the situation?

I read up on a few threads about the throttle body sensors going bad, which in turn messes with the ECU and doesn't send enough fuel to the system.

Thoughts?
 
#9 ·
I believe they checked the coils at the last service. They also checked for a vacuum leak at the time found nothing.

now I did some trouble shooting during the past week. It doesn't seem to make a difference whether it's in neutral or drive when stopped. It does seem to be more pronounced when the AC is on. It was running rough at a light and I switched the AC off and it almost completely stopped running rough. The RPMs also dropped to between 700-800 but it was smoother than the idle at 900ish.

Any thoughts on how the extra load on the engine from the AC might create the situation?

I read up on a few threads about the throttle body sensors going bad, which in turn messes with the ECU and doesn't send enough fuel to the system.

Thoughts?
I ran into a similar issue with my SRT-4 (one of many issues). It turned out to be the wiring harness for the TPS (throttle positioning sensor). This was resolved by replacing the harness... and resolved after being bent over and rammed in my *** by a previous Dodge dealership :eek:

I suggest going that route... the symptons are earily similar!
 
#8 ·
After the test in the fall it came back with misfires in two of the cylinders. That's when we replaced the plugs as noted above. The shop specializes in Saab's but services more older models than they do late. I believe the said the coils were fine, but at $70ish a pop it's a good starting point. Better than dropping cash on a throttle body or chasing the gremlin via the tranny. Hopefully I can get it handled this week.

Aside from trouble shotting this issue for the past year and a half I love the car!
 
#11 ·
stock coil packs blow on these cars often its a common problem and they usually only need to be replaced once new coil packs for the v6 are about 34 bucks. if you had misfires i would blame your coils that are probably starting to go.
 
#13 ·
I'm gonna start with the coil packs, based on individual cylinders misfiring on the original test.

I would think that if it is the wiring harness for the TPS, there would be an issue engine wide, not cylinder specific. But maybe not. The harness will be the next move if the coil packs aren't the problem.

I appreciate the feedback and breakdown!
 
#14 ·
coilpacks are probably the issue i have a sputtering problem at idle and stutter below 1800 rpm if i gas it... stutter til i reach about 2000 rpms then it smooths out from any gear.... missfire heaven in that rpm range. You can easily hear it if you have an exhaust. Gonna order mine today..
 
#15 ·
I called to setup my appointment and threw out the coil pack theory to the head mechanic. "GM has been having coil pack issues for years" and "that's probably a good place to try next" came out of his mouth.

- Anyone have any thoughts on doing the plugs again? Any chance a bad coil would damage a plug? The plugs have about 6,000-8,000 miles on them and they the work is right there anyway?
 
#23 ·
PLEASE tell me you didn't pay $1000 for new coils and the install. Oh my dear god please tell me that wasn't all that was done. There is no install for coils, it takes literally 5-10 minutes.... I know 2.0t coils can be $70-$100 a piece but I'm pretty sure the 6cyl coils are no where near that... Dude.... Please tell us you didn't spend $1080 on 6 coils and install. $1000 to me is a brand new colt 6920 ar15 or a full cat back exhaust and downpipe. Pleaseeeee
 
#28 ·
Im facepalming so hard right now.


V6 coils are around $40-45 on average with warranty.

Coils 1,2,4,6 take about 3 minutes to swap out. Coil 3 and 5 is more difficult a bit time consuming cause of the vacuum lines.

But goddamn, $1080 for that job. Holy ****.



Bleedgreen I can't believe you spent so much money on that job. It could've been done by many of us for a lot cheaper.
 
#29 ·
Saab 93 2006 won't start at times and idle till car reaches past 50mph

My Saab 93 having problems, some days vehicle will start I drive it say 10miles then after I stop somewhere and shut down car, won't start back at times have had crank position sensor replaced, also fuel pump, also at times when I'm driving car the vehicle will cut off completely ?
 
#30 ·
My Saab 93 having problems, some days vehicle will start I drive it say 10miles then after I stop somewhere and shut down car, won't start back at times have had crank position sensor replaced, also fuel pump, also at times when I'm driving car the vehicle will cut off completely ?
This is a V6? Need to get a diagnoses by a Tech II scan tool.
 
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